Dataset on the synthesis and physicochemical characterization of blank and curcumin encapsulated sericin nanoparticles obtained from Philosamia ricini silkworm cocoons

The dataset presents the synthesis and physicochemical characterization of blank and curcumin encapsulated sericin protein nanoparticles obtained from Philosamia ricini (also known as Ahimsa silk or Peace silk or Eri). Reports on application of sericin protein obtained from P. ricini are scanty at best. Sericin was extracted from the cocoons by high temperature and high pressure method. Synthesis of sericin nanoparticles was carried out by desolvation method using acetone as the desolvating agent. Curcumin was used as a hydrophobic model drug and was encapsulated into the sericin nanoparticles. Physicochemical characterization of the blank and curcumin encapsulated sericin nanoparticles were carried out by different instrumental analyses. The size and surface charges of sericin nanoparticles changed with the variation of applied sericin concentration. Encapsulation efficiency and loading capacity of the encapsulated sericin nanoparticles showed variation with curcumin concentration. The obtained data indicated the applicative potentials of sericin protein extracted from Philosamia ricini silkworm cocoons.


a b s t r a c t
The dataset presents the synthesis and physicochemical characterization of blank and curcumin encapsulated sericin protein nanoparticles obtained from Philosamia ricini (also known as Ahimsa silk or Peace silk or Eri). Reports on application of sericin protein obtained from P. ricini are scanty at best. Sericin was extracted from the cocoons by high temperature and high pressure method. Synthesis of sericin nanoparticles was carried out by desolvation method using acetone as the desolvating agent. Curcumin was used as a hydrophobic model drug and was encapsulated into the sericin nanoparticles. Physicochemical characterization of the blank and curcumin encapsulated sericin nanoparticles were carried out by different instrumental analyses. The size and surface charges of sericin nanoparticles changed with the variation of applied sericin concentration. Encapsulation efficiency and loading capacity of the encapsulated sericin nanoparticles showed variation with curcumin concentration. The obtained data indicated the applicative potentials of sericin protein extracted from Philosamia ricini silkworm cocoons.
© 2019 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4.0/).

Data
Sericin protein is a waste product of silk industry and about 25e30% of waste sericin is generated during degumming process of silk [1]. The sericin protein used was extracted from P. ricini cocoons employing the high temperature and high pressure (HTHP) method (Fig. 1aec). The molecular weight distribution of the extracted sericin was investigated using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis (Fig. 2). Synthesis of blank sericin nanoparticles was carried out by desolvation method using acetone as the desolvating agent. The physicochemical characteristics of the synthesized sericin nanoparticles were investigated through instrumental analyses viz, SEM (Figs. 3e6), Zetasizer (Fig. 7) and FTIR (Fig. 8). Curcumin was used as the model hydrophobic drug for investigating the applicability of the sericin nanoparticles as nano drug carrier. Curcumin encapsulated nanoparticles were prepared by desolvation method with varying concentrations of curcumin solubilized in acetone of (Fig. 9). The encapsulation efficiency (EE %) and loading capacity (LC %) were calculated using standard methods (Tables 3 and 4).

Extraction of sericin protein from silkworm cocoons
The autoclave method or high temperature and high pressure (HTHP) method of degumming was used for sericin extraction from Eri silkworm cocoons [3]. The cocoons were manually cleaned and cut Specifications Value of the data Sericin is a fibrous hydrophilic protein with intermittent hydrophobic domains, holding tremendous potential for fundamental research [2]. The data on physicochemical characterization of the blank and curcumin encapsulated sericin nanoparticles presented here could be experimented with other hydrophobic drug molecules for application in the fields of drug delivery, food preservation and antimicrobial activity The present dataset could be useful for design and development of sericin or other hydrophilic protein based nanocarriers with applicative potentials in drug delivery, food preservation, and nutraceuticals, among others Further studies could shed light on the b-sheet transition of Eri sericin as well as the type of interaction occurring between the sericin and curcumin molecules Sericin being soluble in water and reportedly to have a strong emulsifying property, the present dataset could provide the fundamentals for preparation of emulsions of oil-in-water type with wide applications into smaller pieces and autoclaved (60 mins, 15 psi, 121 ± 1 C) at 1:50 ratio of sericin to water (w/v). The autoclaved solution containing sericin was filtered to remove any debris or stray fibers through Whatman filter paper no. 42 (Fig. 1a). The filtrate was lyophilized to obtain pure sericin powder and stored at 4 C until further use (Table 1).

Molecular weight distribution (MWD) of sericin
The MWD of the extracted sericin was investigated for fractionation due to the HTHP method of sericin extraction by SDS-PAGE [4] (Fig. 2).

Preparation of sericin nanoparticles
Sericin nanoparticles were synthesized by a one-step desolvation method using acetone as the desolvating agent [5]. 20 mL of varying concentrations of sericin solution (0.5, 1.0, 1.5 and 2.0 mg mL À1 )  was prepared to which 6 mL of acetone (30% v/v) was added dropwise while on constant stirring at 700e800 rpm. The suspension was kept under stirring condition for about 6 hours to volatilize the acetone. The sericin nanoparticles were collected and washed by centrifugation and used for further experiments.

Physicochemical characterization of blank and curcumin encapsulated sericin nanoparticles
The physicochemical characterization of blank and curcumin encapsulated sericin nanoparticles were carried out by different instrumental analyses. Morphological details (size, shape and aggregation) of the blank and encapsulated sericin nanoparticles were investigated by scanning electron microscopy (SEM, ZEISS Evo MA 10) (Figs. 3e6). The SEM samples for both the blank and curcumin  encapsulated sericin nanoparticles were prepared according to standard procedures [6]. UVeVis spectrophotometry confirmed presence of in the curcumin encapsulated nanoparticle suspension. Zetasizer (Malvern, ZEN3690) was used to determine the hydrodynamic size range and surface charge (zeta potential) of the blank sericin nanoparticles (Table 2, Fig. 7). Fourier transform infrared (FTIR) analysis of sericin monomer and blank sericin nanoparticles was performed (FTIR, Thermo Scientific, Nicolet 6700 FT-IR) under attenuated total reflection (ATR) mode as described in literature [7] (Fig. 8).

Curcumin encapsulation
Curcumin encapsulation was done with a constant sericin concentration of 1.0 mg mL À1 and varying concentrations of curcumin viz. 25 mM, 50 mM, 100 mM, 200 mM, 400 mM by desolvation method using acetone as the desolvating agent (Fig. 9).

Statistical analysis
Data are presented as mean ± SD values of the three independent experiments conducted in triplicates.