Freezing

Example 1

The particles are synthesized by adding between about 5 mg and about 20 mg of rituximab (or non-specific IgG) to 20 mg of ABRAXANE. Saline is then added to a final volume of 2 ml for a final concentration of 10 mg/ml ABRAXANE, and the mixture is allowed to incubate at room temperature for 30 minutes to allow particle formation. Particles average about 160 nm and are termed “AR160” nanoparticles.

Optionally, the composition is divided into aliquots and frozen at −80° C. Once frozen the aliquots are optionally lyophilized overnight with the Virtis 3L benchtop lyophilizer (SP Scientific, Warmister, PA) with the refrigeration on. A lyophilized preparation is generated.

The dried aliquots are stored at room temperature. These samples are reconstituted in saline at room temperature for 30 minutes, followed by centrifugation for 7 minutes at 2000×g. The resulting sample is then resuspended in the appropriate buffer, as needed.

Example 1

Cell-free fractions were prepared as previously described (25). Briefly, Lactobacillus acidophilus strain La-5 was grown overnight in modified DeMann, Rogosa and Sharpe medium. (mMRS; 10 g peptone from casein, 8 g meat extract, 4 g yeast extract, 8 g D(+)-glucose, 2 g dipotassium hydrogen phosphate, 2 g di-ammonium hydrogen citrate, 5 g sodium acetate, 0.2 g magnesium sulfate, 0.04 g manganese sulfate in 1 L distilled water) (MRS; BD Diagnostic Systems, Sparks, MD). The overnight culture was diluted 1:100 in fresh medium. When the culture grew to an optical density at 600 nm (OD₆₀₀) of 1.6 (1.2×10⁸ cells/ml), the cells were harvested by centrifugation at 6,000×g for 10 min at 4° C. The supernatant was sterilized by filtering through a 0.2-μm-pore-size filter (Millipore, Bioscience Division, Mississauga, ON, Canada) and will be referred to as cell-free spent medium (CFSM). Two litres of L. acidophilus La-5 CFSM was collected and freeze-dried (Unitop 600 SL, VirTis Co., Inc. Gardiner, NY., USA). The freeze-dried CFSM was reconstituted with 200 ml of 18-Ω water. The total protein content of the reconstituted CFSM was quantified using the BioRad DC protein assay kit II (Bio-Rad Laboratories Ltd., Mississauga, ON, Canada). Freeze-dried CFSM was stored at −20° C. prior to the assays.

Example 19

The above silk solutions were transformed to a silk powder through lyophilization to remove bulk water and chopping to small pieces with a blender. pH was adjusted with sodium hydroxide. Low molecular weight silk (−25 kDa) was soluble while high molecular weight silk (−60 kDa) was not.

The lyophilized silk powder can be advantageous for enhanced storage control ranging from 10 days to 10 years depending on storage and shipment conditions. The lyophilized silk powder can also be used as a raw ingredient in the pharmaceutical, medical, consumer, and electronic markets. Additionally, lyophilized silk powder can be re-suspended in water, HFIP, or an organic solution following storage to create silk solutions of varying concentrations, including higher concentration solutions than those produced initially.

In an embodiment, aqueous pure silk fibroin-based protein fragment solutions of the present disclosure comprising 1%, 3%, and 5% silk by weight were each dispensed into a 1.8 L Lyoguard trays, respectively. All 3 trays were placed in a 12 ft² lyophilizer and a single run performed. The product was frozen with a shelf temperature of ≤−40° C. and held for 2 hours. The compositions were then lyophilized at a shelf temperature of −20° C., with a 3 hour ramp and held for 20 hours, and subsequently dried at a temperature of 30° C., with a 5 hour ramp and held for about 34 hours. Trays were removed and stored at ambient conditions until further processing. Each of the resultant lyophilized silk fragment compositions were able to dissolve in aqueous solvent and organic solvent to reconstitute silk fragment solutions between 0.1 wt % and 8 wt %. Heating and mixing were not required but were used to accelerate the dissolving rate. All solutions were shelf-stable at ambient conditions.

In an embodiment, an aqueous pure silk fibroin-based protein fragment solution of the present disclosure, fabricated using a method of the present disclosure with a 30 minute boil, has a molecular weight of about 57 kDa, a polydispersity of about 1.6, inorganic and organic residuals of less than 500 ppm, and a light amber color.

In an embodiment, an aqueous pure silk fibroin-based protein fragment solution of the present disclosure, fabricated using a method of the present disclosure with a 60 minute boil, has a molecular weight of about 25 kDa, a polydispersity of about 2.4, inorganic and organic residuals of less than 500 ppm, and a light amber color.