Date of Publication
3-30-2026
Document Type
Master's Thesis
Degree Name
Master of Science in Chemistry
Subject Categories
Chemistry
College
College of Science
Department/Unit
Chemistry
Thesis Advisor
Aldrin P. Bonto
Joseph Rey H. Sta. Agueda
Defense Panel Chair
Derrick Ethelbert C. Yu
Defense Panel Member
Francis M. Dela Rosa
Kathrina Lois M. Taaca
Abstract (English)
Amylopectin, which accounts for approximately 70–80% of starch, is a renewable biopolymer with potential for biomedical and biofabrication applications. However, its native form exhibits limited solubility, retrogradation, and poor printability. TEMPO-mediated oxidation provides a regioselective approach for introducing carboxyl groups at the C6 position of glucose units, enabling modification of structural and physicochemical properties while preserving the polysaccharide backbone. This study evaluates the feasibility of TEMPO-functionalized amylopectin as a bioink component, focusing on the relationship between oxidation parameters and two (2) metrics used to assess oxidation degree. A three-factor, three-level experimental design was employed, varying incubation time (1–3 h), temperature (5–15 °C), and oxidant concentration (0.1–10% v/v). The response variables included carboxyl content, measured by acid–base titration, and normalized carbonyl peak height, measured by Fourier transform infrared spectroscopy (FTIR). Titration results revealed carboxyl contents ranging from approximately 1.02% to 19.88%, with a statistically significant interaction observed between incubation time and oxidant concentration (p ≈ 0.022). FTIR analysis confirmed carbonyl and carboxyl formation, with normalized peak intensities near 1750 cm⁻¹ indicating a localized response region between samples S22–S27, indicative of the oxidation process. While loss of short-range double helices precedes large-scale crystalline disruption, as evidenced by the substantial decrease in double helix degree (from 1.083 to 0.1082) and in ordered structure index (from 0.05547 to 0.01177). Complementarily, wide-angle X-ray scattering (WAXS) demonstrated partial disruption of crystalline domains in optimized samples, as evidenced by reduced crystallinity and presence of peak broadening, suggesting successful functionalization without complete structural collapse. In the microstructural analysis, scanning electron microscopy (SEM) also revealed significant changes when compared to the native amylopectin features, demonstrating a drastic decrease in crystallinity and increase in disordered packing. Overall, TEMPO oxidation enables tunable modification of amylopectin across chemical, structural, and functional scales. The identification of localized optimization regions underscores the need to refine the experimental design to predict oxidation-dependent printability better, supporting the potential of TEMPO-functionalized amylopectin as a viable bioink precursor.
Abstract Format
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Abstract (Filipino)
Ang amylopectin, na bumubuo ng humigit-kumulang 70–80% ng starch, ay isang renewable biopolymer na may potensyal para sa mga aplikasyon sa biomedical at biofabrication. Gayunpaman, ang likas na anyo nito ay nagpapakita ng limitadong solubility, retrogradation, at mahinang printability. Ang TEMPO-mediated oxidation ay nagbibigay ng isang regioselective na paraan para sa paglalagay ng mga carboxyl group sa C6 position ng mga glucose unit, na nagbibigay-daan sa pagbabago ng mga istruktural at pisikokemikal na katangian habang napapanatili ang polysaccharide backbone.
Sinusuri ng pag-aaral na ito ang feasibility ng TEMPO-functionalized amylopectin bilang isang bioink component, na nakatuon sa ugnayan sa pagitan ng mga parameter ng oxidation at dalawang (2) sukatan na ginagamit upang matukoy ang antas ng oxidation. Isang three-factor, three-level experimental design ang ginamit, kung saan binago ang incubation time (1–3 oras), temperature (5–15 °C), at oxidant concentration (0.1–10% v/v). Kabilang sa mga response variable ang carboxyl content, na sinukat sa pamamagitan ng acid–base titration, at normalized carbonyl peak height, na sinukat gamit ang Fourier transform infrared spectroscopy (FTIR).
Ipinakita ng mga resulta ng titration ang carboxyl contents na mula humigit-kumulang 1.02% hanggang 19.88%, kung saan may statistically significant interaction na naobserbahan sa pagitan ng incubation time at oxidant concentration (p ≈ 0.022). Kinumpirma ng FTIR analysis ang pagbuo ng carbonyl at carboxyl, kung saan ang normalized peak intensities malapit sa 1750 cm⁻¹ ay nagpapakita ng isang localized response region sa pagitan ng mga sample S22–S27, na nagpapahiwatig ng proseso ng oxidation.
Habang ang pagkawala ng short-range double helices ay nauuna sa malakihang crystalline disruption, ito ay napatunayan ng malaking pagbaba sa double helix degree (mula 1.083 hanggang 0.1082) at sa ordered structure index (mula 0.05547 hanggang 0.01177). Bilang karagdagang ebidensya, ipinakita ng wide-angle X-ray scattering (WAXS) ang bahagyang pagkasira ng crystalline domains sa mga optimized sample, na makikita sa pagbaba ng crystallinity at paglawak ng mga peak, na nagpapahiwatig ng matagumpay na functionalization nang hindi tuluyang nasisira ang estruktura.
Sa microstructural analysis, ipinakita rin ng scanning electron microscopy (SEM) ang mahahalagang pagbabago kumpara sa mga katangian ng native amylopectin, kabilang ang malaking pagbaba sa crystallinity at pagtaas ng disordered packing. Sa kabuuan, ang TEMPO oxidation ay nagbibigay-daan sa naiaayos (tunable) na pagbabago ng amylopectin sa antas ng kemikal, istruktural, at functional. Ang pagkilala sa mga localized optimization regions ay nagpapakita ng pangangailangan na higit pang pinuhin ang experimental design upang mas mahusay na mahulaan ang oxidation-dependent printability, na sumusuporta sa potensyal ng TEMPO-functionalized amylopectin bilang isang maaaring gamitin (viable) na bioink precursor.
Abstract Format
html
Language
English
Format
Electronic
Keywords
Oxidation; Biopolymers
Recommended Citation
Carranza, M. S. (2026). Physicochemical characterization of TEMPO-oxidized amylopectin as a viable bioink precursor. Retrieved from https://animorepository.dlsu.edu.ph/etdm_chem/36
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Embargo Period
4-26-2028
