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- Russo, Giovanni, et al.
(author)
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Tuning Pluronic F127 phase transitions by adding physiological amounts of salts : A rheology, SAXS, and NMR investigation
- 2024
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In: European Polymer Journal. - 0014-3057. ; 204
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Journal article (peer-reviewed)abstract
- Specific ion (Hofmeister) effects in colloid and biological systems represented a scientific challenge for more than 100 years. Recently, possible applications, based on their rationalization, are emerging. Here, Cl-, SO42-, SCN- anions and Na+, K+, Mg2+ cations are added at physiological concentration (∼0.15 mol/kg) to Pluronic F127 20 wt% aqueous solutions to suitably tune phase transitions for a smart drug delivery platform. Rheological measurements, along with SAXS and NMR self-diffusion experiments, are used to carefully characterize the prepared F127/salt-based formulations. The critical micellar temperature (cmt), the hard-gel formation temperature (Thg), liquid crystal structures, and self-diffusion coefficients are determined. The cmt and Thg values of F127/salt formulations are lower than that of F127 20 wt% sample, following an anionic Hofmeister series: SO42- < Cl- < SCN-. All added salts significantly increase storage modulus and complex viscosity with maximum values occurring at T around 40 °C. SAXS data confirm that added salts preserve cubic liquid crystal phases. NMR self-diffusion analysis highlights that the intermolecular interactions and mobility of F127 unimers/aggregates are ion specific at 16 °C but not at 40 °C. These findings suggest that F127/salt-based formulations may constitute a versatile thermosensitive platform for drug delivery able to assure sustained release in topical or surgery administrations, in the range of temperatures 30–45 °C.
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- Salis, Benedetta, et al.
(author)
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Referred sensation location can be altered by a strong heterotopic nociceptive stimulus : implications for clinical pain conditions
- 2023
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In: Pain. - : Wolters Kluwer. - 0304-3959 .- 1872-6623. ; 164:5, s. e242-e250
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Journal article (peer-reviewed)abstract
- ABSTRACT: Referred sensations (RS) are a common clinical phenomenon in patients with musculoskeletal pain, however the underlying mechanisms of RS and implications for diagnosis and management are poorly understood. The location of referral seems to have a preferred site but studies have suggested it can be redirected to a site of previous injury and pain. However, it is not known if the same phenomenon can occur for a much shorter-lasting painful stimulus in the trigeminal system. The aim of this study was to assess if RS location elicited with standardized palpation of the masseter muscle could be altered following a 10-minute painful infusion of hypertonic saline into the retromolar region. A total of 56 healthy participants participated in this cross-over study performed in two sessions separated by one hour. At each session, baseline and post-infusion assessments of masseter muscle mechanical sensitivity were performed using two different forces (0.5 kg and 2 kg). Between assessments, hypertonic saline (5%) or isotonic saline (control) were continuously infused into the retromolar region. Participants were asked to rate their mechanical sensitivity and any RS they experienced as well as to draw the location of the RS. No difference in mechanical sensitivity or RS frequency was seen after either infusion when compared to before infusion. However, the RS location was displaced on average 1.2 cm between the baseline and post-infusion assessments for the hypertonic saline infusion, which was significantly increased when compared to the isotonic saline infusion which was on average 0.4 cm. These novel findings indicate the potential to modify the location of RS in the trigeminal system following a relatively brief noxious input. Clinicians need to be aware of the possible rerouting of RS in complex orofacial pain patients.
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