Characterization of temperature induced changes in liposomes coated with poly( N -isopropylacrylamide- co -methacrylic acid)

Klemetsrud, Therese; Hiorth, Marianne; Smistad, Gro; Kjøniksen, Anna–Lena

doi:10.1016/j.jcis.2015.03.005

Cited by 9 publications

(4 citation statements)

References 67 publications

(121 reference statements)

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“…Since the DPPC liposomes in the present work were coated immediately after cooling to room temperature after extrusion, this suggests that the size of the DPPC liposomes at the time of being coated most probably was around 161 nm, i.e., at the same level as the SoyPC liposomes. This means that both the SoyPC and the DPPC liposomes increased in size after coating, which is also in line with what has been shown for other systems in the literature [12,15,17,39,58]. For both types of lipids the HM-C8-HEC coated liposomes ended up larger than the corresponding HM-C16-HEC coated samples and with larger PDI values (Table 1).…”

Section: Figuresupporting

confidence: 90%

“…The DPPC liposomes in the gel phase have a faceted polyhedral appearance [53,57], which may facilitate the aggregation due to larger contact areas. When heating the DPPC liposomes to above the T c, the liposomes become more round [17,57] and the liposomes are expected to disaggregate due to thicker hydration layer and stronger repulsive forces [55,56], and maybe also because of the smaller contact areas as a result of the spherical shape. In order to determine the "real" size of the DPPC liposomes the sample was first heated to 50 °C (above the T c of the DPPC) to promote disaggregation.…”

Section: Resultsmentioning

confidence: 99%

“…To increase the stability, both in vivo and in vitro, liposomes have been coated with polymers [10][11][12]. The polymers forming the coating may be attached to the liposomal surface by electrostatic deposition, e.g., chitosan [10,13,14], pectin [15,16], poly(N-isopropylacrylamide (PNIPAAM)-comethacrylic acid) [17], and alginate [18]. Charged polymer coatings have also been introduced for improving the mucoadhesive properties of the system [19][20][21] and for formulation of pH sensitive [22] and temperature sensitive delivery systems [23].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Liposomes coated with hydrophobically modified hydroxyethyl cellulose: Influence of hydrophobic chain length and degree of modification

Smistad

Nyström

Zhu

et al. 2017

Colloids and Surfaces B: Biointerfaces

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Nanoparticulate systems with an uncharged hydrophilic surface may have a great potential in mucosal drug delivery. In the present study liposomes were coated with hydrophobically modified hydroxyethyl cellulose (HM-HEC) to create a sterically stabilized liposomal system with an uncharged surface. The aim was to clarify the influence of the amount of hydrophobic modification of HEC and the length of the hydrophobic moiety, on the stability of the system and on the release properties. HM-HEC with different degrees of hydrophobic modification (1 and 2 mole%) and hydrophobic groups with different chain lengths (C8, C12, C16) were included in the study, as well as fluid phase and gel phase liposomes. Both types of liposomes were successfully coated with HM-HEC containing 1 mole% of hydrophobic groups, while 2 mole% did not work for the intended pharmaceutical applications. The polymer coated gel phase liposomes were stable (size, zeta potential, leakage) for 24 weeks at 4 °C, with no differences between the C8 and C16 HM-HEC coating. For the fluid phase liposomes a size increase was observed after 24 weeks at 4 °C for all formulations; the C8 HM-HEC coated liposomes increased the most. No differences in the leakage during storage at 4 °C or in the release at 35 °C, were observed between the fluid phase formulations. To conclude; HM-HEC with a shorter hydrophobic chain length resulted in a less stable product for the fluid phase liposomes, while no influence of the chain length was observed for the gel phase liposomes (1 mole% HM).

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Section: Figuresupporting

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Liposomes coated with hydrophobically modified hydroxyethyl cellulose: Influence of hydrophobic chain length and degree of modification

Smistad

Nyström

Zhu

et al. 2017

Colloids and Surfaces B: Biointerfaces

Self Cite

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“…However, Han et al showed that the hydrophobic isopropyl groups of NIPAM can also fix the polymer in a liposome membrane [ 167 , 168 ]. Klemetsrud et al [ 169 ] used electrostatic interaction for modification of positively charged liposomes containing 10 mol% DPTAP with the negatively charged NIPAM-co-MAA.…”

Section: Temperature Sensitive Liposomes Sensitized By Temperaturementioning

confidence: 99%

Hyperthermia and Temperature-Sensitive Nanomaterials for Spatiotemporal Drug Delivery to Solid Tumors

Amin¹,

Huang²,

Seynhaeve³

et al. 2020

Pharmaceutics

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Nanotechnology has great capability in formulation, reduction of side effects, and enhancing pharmacokinetics of chemotherapeutics by designing stable or long circulating nano-carriers. However, effective drug delivery at the cellular level by means of such carriers is still unsatisfactory. One promising approach is using spatiotemporal drug release by means of nanoparticles with the capacity for content release triggered by internal or external stimuli. Among different stimuli, interests for application of external heat, hyperthermia, is growing. Advanced technology, ease of application and most importantly high level of control over applied heat, and as a result triggered release, and the adjuvant effect of hyperthermia in enhancing therapeutic response of chemotherapeutics, i.e., thermochemotherapy, make hyperthermia a great stimulus for triggered drug release. Therefore, a variety of temperature sensitive nano-carriers, lipid or/and polymeric based, have been fabricated and studied. Importantly, in order to achieve an efficient therapeutic outcome, and taking the advantages of thermochemotherapy into consideration, release characteristics from nano-carriers should fit with applicable clinical thermal setting. Here we introduce and discuss the application of the three most studied temperature sensitive nanoparticles with emphasis on release behavior and its importance regarding applicability and therapeutic potentials.

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Cationic effect of an ionic copolymer with a temperature-responsive charateristic on the LCST value: A broad LCST spectrum of 35 to 46 °C

Seo

Shin

2015

Macromol. Res.

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Characterization of temperature induced changes in liposomes coated with poly( N -isopropylacrylamide- co -methacrylic acid)

Cited by 9 publications

References 67 publications

Liposomes coated with hydrophobically modified hydroxyethyl cellulose: Influence of hydrophobic chain length and degree of modification

Liposomes coated with hydrophobically modified hydroxyethyl cellulose: Influence of hydrophobic chain length and degree of modification

Hyperthermia and Temperature-Sensitive Nanomaterials for Spatiotemporal Drug Delivery to Solid Tumors

Cationic effect of an ionic copolymer with a temperature-responsive charateristic on the LCST value: A broad LCST spectrum of 35 to 46 °C

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