Date of Graduation
12-2024
Document Type
Thesis
Degree Name
Master of Science in Cell & Molecular Biology (MS)
Degree Level
Graduate
Department
Cell & Molecular Biology
Advisor/Mentor
Kim, Jin-Woo
Committee Member
Sakon, Joshua
Second Committee Member
Lee, Sun-Ok
Keywords
Microencapsulation; Probiotics delivery; Hydrogel microspheres; Cellulose nanocrystals; Controlled release systems; Gastrointestinal tract
Abstract
Microencapsulation has garnered significant interest, with oral probiotics delivery systems showing enormous potential to help restore the gut microbiome. This method holds vast potential to protect and release specific microbial strains to the desired target site (i.e., colon) within the gastrointestinal tract (GIT). However, current encapsulation methodologies, utilizing either synthetic or biological materials as carriers, encounter challenges such as suboptimal encapsulation efficiency, premature probiotic release, and inadequate control over release kinetics. In this work, hydrogel microsphere (HM) composites of different cellulose nanocrystal (CNC) forms (i.e., colloidal (c), and crosslinked (x)) and alginate (ALG) were used as advanced controlled release systems (CRSs). These carrier systems effectively encapsulated and protected probiotic cells before releasing them to the desired target site within the GIT. E. coli Nissle 1917, a non-pathogenic gram-negative probiotic strain, was used as the model organism for encapsulation in the HMs. An empirical model based on response surface methodology (RSM) was developed to optimize and investigate the effect of flow rate, cell concentration, and weight ratio of cCNC/ALG and xCNC/ALG on sphericity of probiotics encapsulated HMs. The in-vitro release behavior of various optimized probiotics encapsulated HMs was studied by sequential incubation in simulated gastric fluid (SGF, pH ~2.4) and simulated intestinal fluid (SIF, pH ~7.4), mimicking the natural journey through the GIT. Experimental results indicated that cCNC/ALG and xCNC/ALG HMs maintained stability in acidic conditions (pH ~2.4), retaining over 90% of encapsulated probiotics after 2 hours of incubation in SGF. In contrast, both types of HMs gradually released the cells in alkaline pH, facilitating the controlled release of encapsulated probiotics. These findings underscore the innovative potential of composite HMs to revolutionize targeted probiotic delivery systems in the GIT, addressing longstanding challenges in encapsulation and controlled release.
Citation
Jati, A. (2024). Encapsulation of Probiotics by Cellulose Nanocrystal-Alginate Composite Beads for pH Stimuli-Responsive Delivery. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/5584
