PMID- 18629962
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20100520
LR  - 20080716
IS  - 0006-3592 (Print)
IS  - 0006-3592 (Linking)
VI  - 53
IP  - 1
DP  - 1997 Jan 5
TI  - Preparation of magnetically susceptible polyacrylamide/magnetite beads for use in 
      magnetically stabilized fluidized bed chromatography.
PG  - 79-87
AB  - Spherical polyacrylamide/magnetite (PAM) composite beads, suitable for use in a 
      magnetically stabilized fluidized bed (MSFB), were manufactured by a suspension 
      polymerization method. Yield of beads depended on the type and concentration of 
      buffer used during polymerization as well as the pH. More stabilizer was needed 
      to prevent bead agglomeration as magnetite concentration increased. Bead diameter 
      ranged from less than 60 to 600 microm, depending on reaction conditions, and the 
      bead mean diameter and size distribution decreased with increasing impeller 
      speed. The density and roundness factor of the beads were 1.19 +/- 0.02 g cm(-3) 
      and 1.08 +/- 0.03, respectively. The beads had high magnetization at a low 
      applied magnetic field strength (60 mT at 75 kA m(-1)) and retained little 
      residual magnetization (<2 mT) after the field was removed. Incorporation of 
      magnetite did not significantly affect the physical strength of the beads: the 
      beads' average elastic modulus was 14 +/- 4 kPa, similar to reported values for 
      polyacrylamide gels (15.8 kPa). The beads were stable in a range of buffers from 
      pH 1 to 10 and were resistant to microbial degradation. The fluidization and 
      stabilization behavior of the beads was examined in a bench-scale MSFB. The 
      minimum fluidization velocity (U(mf)) of the beads (0.035 mm s(-1)) allowed the 
      MSFB to be operated at superficial velocities close to those used in HPLC 
      systems. Against expectations, at high superficial velocities, the stabilized bed 
      of the MSFB had a greater expansion than the unstabilized bed. The PAM beads 
      could be derivatized and activated for soybean trypsin inhibitor immobilization 
      by a standard carbodiimide method, and the affinity separation of trypsin from 
      chymotrypsin was demonstrated. The PAM beads show excellent potential for use in 
      MSFB chromatography. (c) 1997 John Wiley & Sons, Inc.
FAU - Cocker, T M
AU  - Cocker TM
AD  - Centre for Technology, University of Waikato, Hamilton, New Zealand.
FAU - Fee, C J
AU  - Fee CJ
FAU - Evans, R A
AU  - Evans RA
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Biotechnol Bioeng
JT  - Biotechnology and bioengineering
JID - 7502021
EDAT- 1997/01/05 00:00
MHDA- 1997/01/05 00:01
CRDT- 1997/01/05 00:00
PHST- 1997/01/05 00:00 [pubmed]
PHST- 1997/01/05 00:01 [medline]
PHST- 1997/01/05 00:00 [entrez]
AID - 10.1002/(SICI)1097-0290(19970105)53:1<79::AID-BIT11>3.0.CO;2-4 [doi]
PST - ppublish
SO  - Biotechnol Bioeng. 1997 Jan 5;53(1):79-87. doi: 
      10.1002/(SICI)1097-0290(19970105)53:1<79::AID-BIT11>3.0.CO;2-4.