Formulation and Characterisation of Antibody-Conjugated Soy Protein Nanoparticles— Implications for Neutralisation of Snake Venom with Improved Efficiency Kadali Renu & Kadiyala Gopi & Gurunathan Jayaraman Received: 21 April 2014 /Accepted: 25 August 2014 # Springer Science+Business Media New York 2014 Abstract The present study reports the formulation of soy protein nanoparticles and its conjugation to antivenom. The conditions for nanoparticle formation were optimised by considering particle size, count rate, stability and zeta potential. The smallest particle size of 70.9±0.9 nm with a zeta potential of −28.0±1.4 mV was obtained at pH 6.2, with NaOH 5.4 % and 28 μg/mg glutaraldehyde. The nanoparticle was conjugated with antisnake venom immunoglobulins (F(ab′) 2 fragments) using 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide. TEM analysis indicated the increased size of particle to 600 nm after conjugation to antiven- om. Further, in vitro studies indicated that conjugated antibodies inhibited the activity of protease, phospholipase and hyaluronidase enzymes of Bungarus caeruleus venom more efficiently than the free antivenom. This is the first report on the use of protein nanoparticles for conjugating snake venom antibodies and their implications for neutralising snake venom enzymes with increased efficiency. Keywords Soy protein nanoparticles . Alkaline hydrolysis . Snake venom . Antivenom . Conjugation . EDC Introduction Biodegradable nanoparticles have gained potential application in the field of targeted and controlled drug delivery [1]. This property has been envisaged because of the smaller size of these particles in the range of 10 to 1,000 nm [2]. The improved performance of the drug molecule delivered by using nanoparticles as carrier is because of their ability to provide better interaction with macromolecular agents such as viruses, membrane and protein complexes [3]. Different polymers such as poly(D,L-lactide-co-glycolide) (PLGA), polylactic acid (PLA), poly-ε-caprolactone (PCL), chitosan, gelatine and albumin have been exploited for the Appl Biochem Biotechnol DOI 10.1007/s12010-014-1207-5 Electronic supplementary material The online version of this article (doi:10.1007/s12010-014-1207-5) contains supplementary material, which is available to authorized users. K. Renu : K. Gopi : G. Jayaraman (*) School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore 632014 Tamil Nadu, India e-mail: gjayaraman@vit.ac.in