Library · Materials, chemistry & fabrication
What Microencapsulation Technologies got wrong, from 24 theses
Summary written by a model from the records below: Across microencapsulation development efforts, researchers frequently encountered challenges including cargo leakage, fragile shell walls, thermal cycling breakdown, and drying-induced structural damage. Wall material limitations and adverse interactions in embedded matrices also hindered encapsulation efficiency, release control, and composite mechanical stability. These records come from graduate theses, 2021 to 2025, each labeled with its degree where the repository states it, and each links to its thesis. They were extracted by language models reading the full text, so treat each as a lead to read, not a verdict.
Plus 9 problems the authors left open, listed at the end.
Failure modes, by theses reporting them
Select a mode to jump to its records.
Payload leakage and inadequate loading capacity compromise microcapsule formulations
Hydrophilic payloads partitioned into external aqueous phases, and methods like polymersome assembly or nanoprecipitation resulted in insufficient cargo concentrations and low loading caps. In other cases, porous multilayer assemblies, hydrogels exceeding entrapment limits, and unfavorable phase transition temperatures triggered substantial payload leakage and phase separation.
Tried and failed
double emulsion solvent evaporation encapsulation applied to hydrophilic small molecule drug loading. Reason: hydrophilic drug partitioned into external aqueous phase, resulting in zero encapsulation
Construction of a highly potent inhalable microparticles combination therapy to treat pulmonary tuberculosis · Imperial · PhD
Considered and rejected
Considered and rejected: Rejected PEG-PLGA and maltodextrin (MDX) polymers for HB encapsulation due to low encapsulation efficiency (<5%) compared to CMC.
PROTECTIVE EFFECTS OF CYANIDIN-3-O-GLUCOSIDE-RICH HASKAP (LONICERA CAERULEA L.) BERRY AGAINST NITROSAMINE-INDUCED LUNG CARCINOGENESIS · Dalhousie · PhD
Considered and rejected
Considered and rejected: Rejected single-step traditional nanoprecipitation due to low drug encapsulation caps (<10 wt%).
Post Exposure Prophylaxis for HIV in the sexual exposure scenario (PEPSE): Development of a novel nanoformulation · Nottingham · Doctorate
Tried and failed
direct liposome encapsulation of proteins applied to protein delivery vehicle preparation. Reason: low phase transition temperature caused cargo leakage, while higher transition temperature lipids caused thermal artifacts
Development of tools and methods for protein identification: From single molecules to in vivo applications · EPFL · PhD
Tried and failed
freeze-thaw polymer hydrogel encapsulation of ionic liquids applied to drug delivery ionogel patches. Outcome: unstable. Reason: ionic liquid concentrations exceeding capacity could not be entrapped, leading to liquid phase separation onto surfaces
Overcoming Barriers in the Gastrointestinal Tract with Ionic Liquids · Harvard · PhD
Considered and rejected
Considered and rejected: Rejected calcium carbonate-PSS/PSS-PAH multilayer microcapsules due to ~58% cargo leakage during layer-by-layer polymer deposition at acidic pH
Bioengineered stimuli-responsive microcarriers for multi-drug delivery towards the treatment of bacterial infections · Imperial · PhD
Thermal cycling and environmental stresses induce barrier layer degradation and failure
Protective thin-film oxide coatings and polymer adhesive encapsulations experienced delamination, outgassing voids, and rupture under thermal cycling or volume expansion. In addition, polymer coatings generated thermal expansion mismatches or presented excessive porosity and thickness that impaired long-term barrier protection.
Tried and failed
thin single-layer ALD oxide encapsulation applied to phase-change materials undergoing volume changes. Outcome: unstable. Reason: mechanical stress from volume expansion caused encapsulation failure, surface roughening, and material volatilization
Improving the reliability of optical phase change materials-based devices · MIT · PhD
Tried and failed
PECVD silicon nitride encapsulation applied to thermal switching of phase change materials. Outcome: unstable. Reason: hydrogen outgassing during thermal cycling created pinholes and voids, degrading optical transparency
Improving the reliability of optical phase change materials-based devices · MIT · PhD
Tried and failed
Polymer adhesive bonding for device encapsulation applied to silicon microfluidic and electrochemical devices. Outcome: unstable. Reason: Fluid penetration, chemical etching, and delamination during thermal cycling caused 50-70% bond failure.
Nanoliter Electronics for Wireless Chemistry · Cornell · PhD
Considered and rejected
Considered and rejected: Rejected leaving the acrylate polymeric coating on FBGs before glass capillary encapsulation due to thermal expansion mismatch, hysteresis, and humidity sensitivity.
Fibre Optic Sensors for Tumour Therapy Monitoring. Applications of Optical Fibre Sensing Technologies to Thermal and Radiotherapy Treatments of Neoplasms · Politecnico di Torino · PhD
Considered and rejected
Considered and rejected: Rejected Parylene-C encapsulation for MOTEs in favor of atomic layer deposition (ALD) of SiO2/Si3N4/Al2O3 because Parylene-C is too thick and porous for microscale longevity.
Circuits for Wireless Sensing · Cornell · PhD
Wall material and excipient defects impair release profiles and shell integrity
Formulations lacking necessary surfactants or using solitary wall materials resulted in deformed particle morphologies, defective emulsification, and rapid unintended payload release. In other systems, polymer gelling generated nondispersible plugs that restricted dissolution, while liquid encapsulants penetrated porous substrates to destabilize electrical properties.
Tried and failed
thermogelling polymer nanoemulsion formulation without surfactant applied to hydrophobic drug encapsulation hydrogels. Outcome: unstable. Reason: insufficient surfactant led to large droplet size and low viscosity, forming tailed particles instead of spheres
Nanoemulsion-Loaded Hydrogels For Advanced Pharmaceutical Formulations · MIT · PhD
Tried and failed
enteric capsule encapsulation of amorphous solid dispersions applied to poorly water-soluble drug formulation. Outcome: worse than baseline. Reason: Polymer gelling formed a nondispersible plug that severely impaired dissolution rate and extent in intestinal fluid.
Repurposing niclosamide : oral and inhaled delivery of niclosamide using hot-melt extrusion and thin film freezing technologies · UT Austin · PhD
Considered and rejected
Considered and rejected: Rejected gelatin capsules for direct Eudragit coating due to poor polymer adhesion
Bowel MRI imaging to investigate drug delivery from coated capsules · Nottingham · PhD
Considered and rejected
Considered and rejected: Rejected using single wall material (such as maltodextrin alone) due to quick gastrointestinal release, deficient emulsification, and lower encapsulation efficiency.
Dietary supplementation of haskap berry (Lonicera caerulea L.) anthocyanin-rich fraction and probiotics attenuates the severity of dextran sulfate sodium-induced acute colitis in Balb/C mice · Dalhousie · Master's
Tried and failed
direct liquid polymer encapsulation without barrier layer applied to porous conductive elastomer composites. Outcome: unstable. Reason: uncured polymer penetrated the porous matrix, causing baseline electrical resistance to drift over time
Soft Sensors in digital healthcare monitoring · Imperial · PhD
Drying and desiccation processes cause shell fracture and core recrystallization
Slow convective air drying allowed active ingredient cores to recrystallize and migrate to the surface, accelerating release and reducing efficiency. Furthermore, spray drying and convective drying methods subjected hollow microcapsules to thermal and shear stresses that resulted in particle collapse and extensive shell breakage.
Tried and failed
slow convective air drying for microencapsulation applied to small molecule active ingredient encapsulation. Outcome: worse than baseline. Reason: slow drying allowed core recrystallization and surface migration, reducing encapsulation efficiency and accelerating release
ENHANCING THE FUNCTIONALITY AND BIOAVAILABILITY OF DIETARY SUPPLEMENTS THROUGH ENCAPSULATION USING VERSATILE PLATFORMS · Cornell · PhD
Considered and rejected
Considered and rejected: Rejected air drying and spray drying for fumed silica microcapsule powder preparation due to capsule collapse and high fracture rates
Synthesizing Semiconductor Nanowires in Hollow Microcapsules via the Geode Process · Georgia Tech · PhD
Tried and failed
spray drying applied to hollow inorganic microcapsules. Outcome: unstable. Reason: thermal and shear stresses caused extensive shell fracturing and particle breakage
Synthesizing Semiconductor Nanowires in Hollow Microcapsules via the Geode Process · Georgia Tech · PhD
Considered and rejected
Considered and rejected: Air-drying for NAC microencapsulation was rejected due to slow drying kinetics causing surface recrystallization and faster release rates than spray drying.
ENHANCING THE FUNCTIONALITY AND BIOAVAILABILITY OF DIETARY SUPPLEMENTS THROUGH ENCAPSULATION USING VERSATILE PLATFORMS · Cornell · PhD
Processing conditions and solvent exposure cause shell rupture and aggregation
Insufficient incubation times or low homogenization speeds generated fragile capsule shells that ruptured and leaked during precipitation and culture. Additionally, sacrificial core dissolution solvents triggered irreversible outer polymer aggregation and flocculation, while pore-sealing coatings exhibited cracking, poor adhesion, and detachment.
Tried and failed
fatty alcohol phase change material coating applied to microcapsule pore sealing. Outcome: unstable. Reason: formed uneven, cracked layers that adhered poorly and detached easily
Bioinspired microrobotic systems for targeted and on-demand cargo delivery · Imperial · PhD
Tried and failed
sacrificial core dissolution in layer-by-layer assembly applied to hollow biopolymer microcapsule fabrication. Outcome: unstable. Reason: Core dissolution solvent caused irreversible bridging flocculation and aggregation of outer polymer layers
Platelet-inspired microparticles for targeted drug delivery to the atherosclerotic plaque · Imperial · PhD
Tried and failed
lower speed homogenization for Pickering emulsion templating applied to hollow microcapsule fabrication. Outcome: unstable. Reason: larger emulsion droplets formed fragile shells that ruptured during antisolvent precipitation
NOVEL STARCH MODIFICATIONS: FABRICATION AND APPLICATIONS · Cornell · PhD
Tried and failed
short-duration culture for bio-capsule shell synthesis applied to bacterial cellulose capsule formation. Outcome: unstable. Reason: insufficient incubation time resulted in thin, fragile shells that ruptured and leaked
Functional Materials Grown from Engineered Bacteria · Harvard · PhD
Embedded microcapsules degrade matrix mechanics and offer limited self-healing longevity
Incorporating microcapsules into structural matrices degraded unhealed fatigue cycles and exposed the capsules to destruction during high-shear mixing. Autonomous chemical self-healing systems also suffered from one-time healing agent consumption, vascular blockage, and severe losses in overall mechanical strength.
Lost to a baseline
Capsule addition reduced unhealed fatigue cycles compared to neat asphalt at certain low loads (e.g., at 621 N, neat SMA resisted 5800 cycles vs 3900 cycles for capsule F)
Optimisation of encapsulated oil properties to maximise asphalt self-healing · Nottingham · PhD
Considered and rejected
Considered and rejected: Extrinsic self-healing (microcapsules) was rejected due to vulnerability to destruction under high-shear mixing and short service lifespan for 20-25 year turbine applications.
Improved Material Formulations for Thick Adhesive Joints in Wind Turbine Blades · EPFL · PhD
Considered and rejected
Considered and rejected: Chemical self-healing mechanisms requiring microcapsules were rejected because self-healing agents are consumed during repair, preventing repeated autonomous healing.
Multifunctional flexible conductive materials for supercapacitors and biosensors · University of Manitoba · PhD
Left open by the authors
Problems the authors named and did not get to.
Left open
Test non-pH responsive, PBS-soluble anticancer drugs for encapsulation and release in pH-responsive methacrylic polymersomes. Blocker: Requires a wet chemistry and biology lab to synthesize polymersomes and perform drug encapsulation/release assays
Self-assembled block copolymers: micelles, polymersomes and gels · Imperial · PhD
Left open
Optimize polymer composition and crosslinking density of poly(amine) microcapsules and evaluate their responsiveness in biologically relevant conditions. Blocker: Requires a wet lab, microfluidic devices, chemical synthesis, and biological testing assays.
Engineering Functional Microcapsules for Controlled Cargo Delivery · Harvard · PhD
Left open
Develop a single-capsule combined formulation of curcumin and ursolic acid lipid microspheres to reduce daily pill burden. Blocker: Requires a wet lab and pharmaceutical manufacturing equipment (hot-melt rotating disk and encapsulation tools).
Phase 1 clinical trial evaluating safety, bioavailability, and gut microbiome with a combination of curcumin and ursolic acid in lipid enhanced capsules · UT Austin · PhD
Left open
Develop encapsulation and on-demand release mechanisms for diverse antibacterial molecules using polyCu-MOF@AgNPs. Blocker: Requires a wet chemistry and biological testing laboratory to synthesize MOFs and test drug release.
New Metal Complexes and Metal-Organic Frameworks (MOFs) with Potential Biological Applications · University of Camerino · PhD
Left open
Develop advanced encapsulation techniques such as nanocarriers, coacervation systems, and dual-phase emulsions to co-stabilize vitamin D and zinc. Blocker: Requires a wet chemistry/food science laboratory and sensory/bioavailability testing apparatus.
Fortified Foods with Vitamin D and Zinc · Cornell · Master's
Left open
Test nanoparticle treatment of chronic biofilm airway infections in βENaC-overexpressing transgenic mice without using artificial bead encapsulation. Blocker: Requires wet lab, animal facility access, and transgenic βENaC-overexpressing mouse models for in vivo infection experiments.
Left open
Optimize encapsulation efficiency of hydrophilic and hydrophobic payloads in DSPC liposomes across varying concentration gradients. Blocker: Requires wet lab equipment for liposome synthesis, extrusion, dialysis, and chemical encapsulation measurement
Biomimetic water-based lubrication: an exploration into vesicle lubrication · Imperial · Doctorate
Left open
Model layer-by-layer assembly and thermal heat transfer performance for phase change material microcapsules with more than two polyelectrolyte layers. Blocker: None
Development of Energy Systems Towards a Low Carbon Future: From Atoms to Policies · Cornell · PhD
Left open
Investigate phase separation kinetics and cargo diffusion pathways in PFH-hexane liquid-shell microcapsules under thermal stimuli. Blocker: Requires wet lab equipment, microfluidic devices, chemical synthesis, and specialized thermal imaging/characterization apparatus.
Engineering Functional Microcapsules for Controlled Cargo Delivery · Harvard · PhD
Who has worked on this
Authors of the public theses cited on this page, most-cited first.
- Cosmin-Constantin Popescu · MIT · PhD · 2025
Improving the reliability of optical phase change materials-based devices - Zhang Wu · Harvard · PhD · 2025
Engineering Functional Microcapsules for Controlled Cargo Delivery - Junyi Wang · Cornell · PhD · 2023
ENHANCING THE FUNCTIONALITY AND BIOAVAILABILITY OF DIETARY SUPPLEMENTS THROUGH ENCAPSULATION USING VERSATILE PLATFORMS - Maritza Mujica · Georgia Tech · PhD · 2021
Synthesizing Semiconductor Nanowires in Hollow Microcapsules via the Geode Process - Yangshuo Hu · Imperial · PhD · 2025
Platelet-inspired microparticles for targeted drug delivery to the atherosclerotic plaque - Shahab Ghajari · Cornell · PhD · 2025
Circuits for Wireless Sensing - Zhi Li · Cornell · Master's · 2025
Fortified Foods with Vitamin D and Zinc - AURORA BELLONE · Politecnico di Torino · PhD · 2025
Fibre Optic Sensors for Tumour Therapy Monitoring. Applications of Optical Fibre Sensing Technologies to Thermal and Radiotherapy Treatments of Neoplasms - Salome Riccarda Püntener · EPFL · PhD · 2024
Development of tools and methods for protein identification: From single molecules to in vivo applications - Jialiang Fan · EPFL · PhD · 2024
Improved Material Formulations for Thick Adhesive Joints in Wind Turbine Blades - Manoj Murali · Imperial · Doctorate · 2023
Biomimetic water-based lubrication: an exploration into vesicle lubrication - Khaled Alzahabi · Imperial · PhD · 2023
Construction of a highly potent inhalable microparticles combination therapy to treat pulmonary tuberculosis
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