S1 Supporting information Porphyrin Functionalized Gelatin Nanoparticle-Based Biodegradable Phototheranostics: Potential Tools for Antimicrobial Photodynamic Therapy Seema Kirar 1 , Neeraj S. Thakur 2 , Joydev K. Laha 3 and Uttam C. Banerjee 1, 2 * 1 Department of Biotechnology 2 Department of Pharmaceutical Technology (Biotechnology) 3 Department of Pharmaceutical Technology (Process Chemistry) National Institute of Pharmaceutical Education and Research (NIPER) Sector-67, S.A.S. Nagar-160062, Punjab, India. * Corresponding author: ucbanerjee@niper.ac.in Table of Contents S1. Chemicals and Instruments ............................................................................................S2 S2. Experimental Section.......................................................................................................S2 S2.1. Synthesis of Gelatin Nanoparticle (GNPs) ..............................................................S2 S2.2. Quantification Study for Gelatin Nanoparticle in 1 mL Solution ........................S2 S3. Characterization of tABpor-GNPs .................................................................................S3 S3.1. Size, Charge ...............................................................................................................S3 S3.2. Attenuated Total Reflection (ATR) .........................................................................S4 S3.3. Circular Dichroism (CD) ..........................................................................................S4 S3.4. Differential Scanning Calorimetry (DSC) ..............................................................S5 S3.5. X-ray Diffractometer (XRD) ....................................................................................S6 S3.6. Energy Dispersive Spectroscopy (EDS) ..................................................................S6 S4. Optimization Study ..........................................................................................................S7 S6. Photostability studies of GNPs ..........................................................................................S8 S7. Fluorescence Studies ........................................................................................................S9 S8. Determination of Singlet Oxygen Generation .............................................................S10 S9. Antimicrobial PDT of tABpor-GNP ............................................................................S11 S10. References.....................................................................................................................S13