After the sonication, the organic solvent was evaporated rapidly using a rotary evaporator to form carboxylated MNC, and free molecules were removed using a centrifugal filter (Centriprep YM-3, 3,000 Da cutoff, Amicon, Millipore, Billerica, MA, USA)[17].
The products were purified using a centrifugal filter (Centriprep YM-3, 3-kDa molecular weight cutoff (MWCO), Amicon, Millipore Corporation, Billerica, MA, USA) in triplicate at 3,000 rpm for 30 min. HA-MRCAs with different molar ratios of HA were fabricated by EDC-NHS chemistry.
The cleaved protein was concentrated and the buffer was changed to buffer 2 using a centrifugal filter device with 5,000 NMWL.
Viral supernatants were collected 48 72 hours after transfection and virus particles were concentrated using a centrifugal filter device (Amicon Ultra-15, Millipore).
The RNAs were concentrated to ∼500 µM using a centrifugal filter unit with a 10,000 MWCO (Millipore, UFC801008), and stored at 4°C or at −20°C in a buffer containing either 50 mM Na HEPES pH 7.5, 25 mM NaCl, 15 mM MgCl2, or 10 mM Na cacodylate pH 5.0 6.5, 10 mM NaCl and 0 5 mM MgCl2.
The solution was filtered through a 0.2 mm filter, and concentrated to ∼200 µM using a centrifugal filter unit with a 30,000 MWCO (Millipore #UFC903096), and stored at 4°C or −20°C in a buffer containing 10 mM Na cacodylate pH 6.5, 10 mM NaCl and 5 mM MgCl2.
Fractions containing the desired protein were combined and concentrated using a centrifugal filtering device, and the buffer was exchanged to LanM start buffer using a gel-filtration column.
Twenty milligrams of PCSNs was diluted in 50% ethanol with distilled water (total volume, 20 ml) and mixed using an ultrasonic water bath for 30 min. The diluted solution was filtered using a centrifugal device (ultrafree centrifugal filter, Durapore PVDF 0.1 μm, Millipore, Billerica, MA, USA) and a centrifuge with a radius of 15.0 cm (13,000 rpm, 15 min).
Radiolabeled PEG 5 -BP-USPIOs can be further PEG 5 -BP-USPIOscentrated to the desired volume using a centrifugal size-exclusion filter with a molecular weight cutoff of 10 kDa (note that around 9% nonsPEG 5 -BP-USPIOsto the filters was found).
Fractions between 4 mL and 16 mL (12 ml in total) were collected and condensed using a Microcon centrifugal filter device (Ultracel YM-10, Millipore) to 0.8 mL for subsequent analysis and RDX reaction.
The cytosolic fraction was concentrated by using a Microcon centrifugal filter (YM-10; Millipore, Bedford, MA, USA).
