PMID- 29257896
OWN - NLM
STAT- MEDLINE
DCOM- 20180917
LR  - 20200306
IS  - 1520-5827 (Electronic)
IS  - 0743-7463 (Print)
IS  - 0743-7463 (Linking)
VI  - 34
IP  - 4
DP  - 2018 Jan 30
TI  - Study of Poly(N-isopropylacrylamide-co-acrylic acid) (pNIPAM) Microgel Particle 
      Induced Deformations of Tissue-Mimicking Phantom by Ultrasound Stimulation.
PG  - 1457-1465
LID - 10.1021/acs.langmuir.7b02801 [doi]
AB  - Poly(N-isopropylacrylamide) (pNIPAm) microgels (microgels) are colloidal 
      particles that have been used extensively for biomedical applications. Typically, 
      these particles are synthesized in the presence of an exogenous cross-linker, 
      such as N,N'-methylenebis(acrylamide) (BIS); however, recent studies have 
      demonstrated that pNIPAm microgels can be synthesized in the absence of an 
      exogenous cross-linker, resulting in the formation of ultralow cross-linked (ULC) 
      particles, which are highly deformable. Microgel deformability has been linked in 
      certain cases to enhanced bioactivity when ULC microgels are used for the 
      creation of biomimetic particles. We hypothesized that ultrasound stimulation of 
      microgels would enhance particle deformation and that the degree of enhancement 
      would negatively correlate with the degree of particle cross-linking. Here, we 
      demonstrate in tissue-mimicking phantoms that using ultrasound insonification 
      causes deformations of ULC microgel particles. Furthermore, the amount of 
      deformation depends on the ultrasound excitation frequency and amplitude and on 
      the concentration of ULC microgel particles. We observed that the amplitude of 
      deformation increases with increasing ULC microgel particle concentration up to 
      2.5 mg/100 mL, but concentrations higher than 2.5 mg/100 mL result in reduced 
      amount of deformation. In addition, we observed that the amplitude of deformation 
      was significantly higher at 1 MHz insonification frequency. We also report that 
      increasing the degree of microgel cross-linking reduces the magnitude of the 
      deformation and increases the optimal concentration required to achieve the 
      largest amount of deformation. Stimulated ULC microgel particle deformation has 
      numerous potential biomedical applications, including enhancement of localized 
      drug delivery and biomimetic activity. These results demonstrate the potential of 
      ultrasound stimulation for such applications.
FAU - Joshi, Aditya
AU  - Joshi A
AUID- ORCID: 0000-0003-4186-7594
FAU - Nandi, Seema
AU  - Nandi S
AD  - Joint Department of Biomedical Engineering, North Carolina State University and 
      University of North Carolina at Chapel Hill , Raleigh, North Carolina 27695, 
      United States.
FAU - Chester, Daniel
AU  - Chester D
AD  - Joint Department of Biomedical Engineering, North Carolina State University and 
      University of North Carolina at Chapel Hill , Raleigh, North Carolina 27695, 
      United States.
FAU - Brown, Ashley C
AU  - Brown AC
AUID- ORCID: 0000-0001-6995-1785
AD  - Joint Department of Biomedical Engineering, North Carolina State University and 
      University of North Carolina at Chapel Hill , Raleigh, North Carolina 27695, 
      United States.
FAU - Muller, Marie
AU  - Muller M
AD  - Joint Department of Biomedical Engineering, North Carolina State University and 
      University of North Carolina at Chapel Hill , Raleigh, North Carolina 27695, 
      United States.
LA  - eng
GR  - R21 AR071017/AR/NIAMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
DEP - 20180109
PL  - United States
TA  - Langmuir
JT  - Langmuir : the ACS journal of surfaces and colloids
JID - 9882736
RN  - 0 (Acrylates)
RN  - 0 (Acrylic Resins)
RN  - 0 (Gels)
RN  - 0 (Polymers)
RN  - 25189-55-3 (poly-N-isopropylacrylamide)
RN  - J94PBK7X8S (acrylic acid)
SB  - IM
MH  - Acrylates/*chemistry
MH  - Acrylic Resins/*chemistry
MH  - Drug Delivery Systems
MH  - Gels/*chemistry
MH  - Polymers/*chemistry
PMC - PMC5983375
MID - NIHMS968726
EDAT- 2017/12/20 06:00
MHDA- 2018/09/18 06:00
PMCR- 2018/06/01
CRDT- 2017/12/20 06:00
PHST- 2017/12/20 06:00 [pubmed]
PHST- 2018/09/18 06:00 [medline]
PHST- 2017/12/20 06:00 [entrez]
PHST- 2018/06/01 00:00 [pmc-release]
AID - 10.1021/acs.langmuir.7b02801 [doi]
PST - ppublish
SO  - Langmuir. 2018 Jan 30;34(4):1457-1465. doi: 10.1021/acs.langmuir.7b02801. Epub 
      2018 Jan 9.