Brukeradvance 3 600 mhz spectrometer

Synthesis of acetal-polyethylene oxide (acPEO, Mn ∼ 5000)
was performed based on the method described by Nagasaki et al.^{34 (link)} with some modifications. Briefly, potassium
naphthalene, used as a catalyst, was freshly prepared before the polymerization.
Pure naphthalene (12.9 mmol) and potassium (14.7 mmol) were added
into 50 mL of anhydrous THF. The reaction was protected under argon
gas and kept running for 24 h. Then, 3,3-diethoxypropanol (2 mmol)
was dissolved in 40 mL of dry THF, and 7 mL of the prepared catalyst
(∼2 mmol) was added dropwise into the reaction solution to
activate the initiator. The flask was purged with argon, and after
10 min of stirring, the flask was transferred into an ice water bath.
Ethylene oxide (228 mmol) was added to the reaction solution. After
48 h, the polymerization was quenched by acidified ethanol. acPEO
was recovered by precipitation in ethyl ether. The product was further
purified by precipitation in diethyl ether. The composition and the
degree of polymerization were confirmed by ¹H NMR (Bruker
Advance III 600 MHz Spectrometer, Bruker Corporation, Billerica, MA).

Optical rotation were determined using an Anton Paar MCP200 automatic polarimeter (Graz, Austria). Ultraviolet spectra were obtained with a Beckman Coulter DU 730 nucleic acid/protein analyzer. IR spectra were recorded with a Bruker Tensor 27 FT-IR spectrometer. ESI-MS were recorded on an Agilent 1290–6420 Triple Quadrupole LC-MS spectrometer (Santa Clara, CA, USA). HRESI-MS experiments were performed using a Bruker Micro TOF-Q mass spectrometer (Bruker Daltonics, Billerica, MA). NMR spectra were recorded on a Bruker Advance III-600 MHz spectrometer (Bruker, Rheinstetten, Germany). Flow cytometric analysis were conducted on an LSR-Fortessa flow cytometer (BD, Franklin Lakes, NJ, USA). MTT and protein quantification were analyzed by a microplate reader (BioTek Synergy H1, BioTek Instruments, Inc., Vermont, USA). Silica gel (100–200 mesh, 200–300 mesh, Qingdao Marine Chemical, Ltd., Qingdao, China), MCI gel (CHP-20P, Mitsubishi Chemical Corp., Tokyo, Japan), and YMC*GEL ODS-A (S-50 μm, 12 nm) (YMC Co., Ltd., Kyoto, Japan) were used for column chromatography. The primary antibodies for cyclin A2, CDK2, p21, Bax, Bcl-2, caspase-3, GAPDH, and horse-radish peroxidase (HRP)-conjugated secondary antibodies were purchased from Cell Signaling Technology (Dancers, MA, USA).