Production of Near-Infrared Sensitive, Core-Shell Vaccine Delivery Platform

Summary

This article describes the protocols used to produce a novel vaccine delivery platform, "polybubbles," to enable delayed burst release. Polyesters including poly(lactic-co-glycolic acid) and polycaprolactone were used to form the polybubbles and small molecules and antigen were used as cargo.

Abstract

Vaccine delivery strategies that can limit the exposure of cargo to organic solvent while enabling novel release profiles are crucial for improving immunization coverage worldwide. Here, a novel injectable, ultraviolet- curable and delayed burst release- enabling vaccine delivery platform called polybubbles is introduced. Cargo was injected into polyester-based polybubbles that were formed in 10% carboxymethycellulose -based aqueous solution. This paper includes protocols to maintain spherical shape of the polybubbles and optimize cargo placement and retention to maximize the amount of cargo within the polybubbles. To ensure safety, chlorinated solvent content within the polybubbles were analyzed using neutron activation analysis. Release studies were conducted with small molecules as cargo within the polybubble to confirm delayed burst release. To further show the potential for on-demand delivery of the cargo, gold nanorods were mixed within the polymer shell to enable near-infrared laser activation.

Introduction

Limited immunization coverage results in the death of 3 million people specifically caused by vaccine-preventable diseases¹. Inadequate storage and transportation conditions lead to wastage of functional vaccines and thus contribute to reduced global immunization. In addition, incomplete vaccination due to not adhering to the required vaccine schedules also causes limited vaccine coverage, specifically in developing countries². Multiple visits to medical personnel are required within the recommended period for receiving booster shots, thus limiting the percentage of population with complete vaccination. Hence, there is a....

Protocol

1. Polycaprolacyone triacrylate (PCLTA) synthesis

1. Dry 3.2 mL of 400 Da polycaprolacyone (PCL) triol overnight at 50 °C in an open 200 mL round bottom flask and K₂CO₃ in a glass vial at 90 °C.
2. Mix the triol with 6.4 mL of dichloromethane (DCM) and 4.246 g of potassium carbonate (K₂CO₃) under argon.
3. Mix 2.72 mL of acryloyl chloride in 27.2 mL of DCM and add dropwise to the reaction mixture in the flask over 5 min.
4. Cover the reac.......

Discussion

Current technologies and challenges
Emulsion-based micro- and nanoparticles have been commonly used as drug delivery carriers. Although release kinetics of the cargo from these devices have been extensively studied, controlling burst release kinetics has been a major challenge¹¹. Cargo versatility and functionality is also limited in emulsion-based systems owing to the exposure of cargo to excess aqueous and organic solvents. Protein-based cargo are often not compatible with.......

Materials

Name	Company	Catalog Number	Comments
1-Step Ultra Tetramethylbezidine (TMB)-Enzyme-Linked Immunosorbent Assay (ELISA) Substrate Solution	Thermo scientific	34028
2-Hydroxy-2-methylpropiophenone	TCI AMERICA	H0991
450 nm Stop Solution for TMB Substrate	Abcam	ab17152
Acryloyl chloride	Sigma Aldrich	A24109-100G
Acriflavine	Chem-Impex International	22916
Anhydrous ethyl ether	Fisher Chemical	E138-500
Anti-HIV1 gp120 antibody conjugated to horseradish peroxidase (HRP)
Bovine serum albumin (BSA)	Fisher BioReagents	BP9700100
BSA-CF488 dye conjugates	Invitrogen	A13100
Bromosalicylic acid	Acros Organics	AC162142500
Carboxymethylcellulose (CMC)	Millipore Sigma	80502-040
Centrimonium bromide (CTAB)	MP Biomedicals	ICN19400480
Chloroform	Fisher Chemical	C2984
Coating buffer	Abcam	ab210899
Dichloromethane (DCM)	Sigma Aldrich	270997-1L
Diethyl ether	Fisher Chemical	E1384
Dodeacyl Amine	Acros Organics	AC117665000
Doxorubicin hydrochloride	Fisher BioReagents	BP251610
L-ascorbic acid	Acros Organics	A61 100
Legato 100 Syringe Pump	KD Scientific	14 831 212
mPEG thiol	Laysan Bio	NC0702454
Nonfat dry milk	Andwin Scientific	NC9022655
Potassium carbonate	Acros Organics	AC424081000
Phosphate saline buffer	Fisher BioReagents	BP3991
(Poly(caprolactone)	Sigma Aldrich	440744-250G
(Poly(caprolactone) triol	Acros Organics	AC190730250
Poly (lactic-co-glycolic acid) diacrylate	CMTec	280050
Potassium carbonate	Acros Organics	AC424081000
Recombinant HIV1 gp120 + gp41 protein	Abcam	ab49054
Silver nitrate	Acros Organics	S181 25
Sodium borohydride	Fisher Chemical	S678 10
Tetrachloroauric acid	Fisher Chemical	G54 1
Trehalose	Acros Organics	NC9022655
Triethyl amine	Acros Organics	AC157910010