Ci a ion: Aboudzadeh, M.A.;
Hamzehlou, S. Special Issue on
“Func ion o Polyme s in
Encapsula ion P ocess”. Polyme s
2022,14, 1178. h ps://doi.o g/
10.3390/polym14061178
Recei ed: 4 Janua y 2022
Accep ed: 27 Feb ua y 2022
Published: 15 Ma ch 2022
Publishe ’s No e: MDPI s ays neu al
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polyme s
Edi o ial
Special Issue on “Func ion o Polyme s in
Encapsula ion P ocess”
M. Ali Aboudzadeh 1and Shaghayegh Hamzehlou 2,*
1CNRS, Ins i u des Sciences Analy iques e de Physico-Chimie pou l’En i onnemen e les Ma é iaux,
Uni e si y Pau & Pays Adou , E2S UPPA, IPREM, UMR5254, 64000 Pau, F ance;
[email p o ec ed]
2Polyma and Kimika Aplika ua Saila, Kimika Fakul a ea, Uni e si y o he Basque Coun y UPV-EHU,
Joxe Ma i Ko a Zen oa, Tolosa Hi ibidea 72, 20018 Donos ia-San Sebas ian, Spain
*Co espondence: [email p o ec ed]
Encapsula ion echnology comp ises enclosing ac i e agen s (co e ma e ials) wi hin
a homogeneous/he e ogeneous ma ix (wall ma e ial) a he mic o/nano scale. In he
las ew yea s encapsula ion has gained a lo o in e es . Using his p ocess, a physical
ba ie is de eloped be ween he inne subs ance and he en i onmen which on one
hand p e en s i s deg ada ion and acili a es i s handling and anspo a ion and on he
o he hand allows he con olled elease o he co e ma e ial in a ce ain ambiance [
1
].
Polyme s may be used o ap he ma e ial o in e es inside he mic o/nano-capsules.
Such encapsula ed sys ems ha e many applica ions in he ields o he ood indus y, d ug
deli e y, ag icul u e, cosme ics, coa ings, adhesi es and so o h. Va ious biopolyme s, such
as algina e, chi osan, ca ageenan, gums, gela in, whey p o ein o s a ch, ac as a ba ie
agains ex e nal condi ions. Encapsula ion in biodeg adable polyme s can also enhance
he pe meabili y and s abili y o he ac i e agen and hus i s bioa ailabili y. Choosing he
igh polyme is e y impo an in his p ocess due o i s impac on a ge deli e y and
con olled elease, and he e o e, on he bioa ailabili y o ac i e agen s. I should ha e he
necessa y p ope ies, such as being non- eac i e wi h he ac i e agen , lexibili y, s abili y,
s eng h, and impe meabili y. I he ac i e agen has applica ion in he ood indus y,
he used polyme should be “gene ally ecognized as sa e” (GRAS), biodeg adable, and
capable o p ese ing he encapsula ed ma e ial om he a mosphe e [2].
The e a e a numbe o chemical, physical o mechanical p ocesses a ailable o encap-
sula ion such as emulsion-sol en e apo a ion/ex ac ion me hods, coace a ion-phase
sepa a ion, sp ay d ying, in e acial and in si u polyme iza ion. The choice o a pa icula
echnique depends on he a ibu es o he polyme and he ac i e agen . The e a e s ill
many aspec s o be de eloped in his ield, which o e new challenges and b eak h ough
oppo uni ies. The main objec i e o his in e disciplina y Special Issue is o b ing oge he ,
a an in e na ional le el, a high-quali y collec ion o e iews and o iginal esea ch a icles
dealing wi h he impo ance o na u al o syn he ic polyme s in encapsula ion p ocesses
and hei applica ions. A deep unde s anding and ele an heo e ical calcula ions o
explo ing he unc ions o he ma e ials (in ol ed in he o mula ions) ha e also been
ob ained by undamen al in es iga ions. The pu pose o his edi o ial is o p o ide a b ie
in oduc ion o each published o accep ed pape and highligh hei majo indings and
disco e ies. In he ollowing, we e iew all he a icles in ou Special Issue, and we belie e
his edi o ial will in e es he b oades possible sec ion o eade ship.
One o he c ucial cha ac e is ics o d ug deli e y sys ems in biomedicine is o impa
he sus ained elease o an encapsula ed d ug. Thus, he sus ained elease enhances he
accumula ion o he d ug a he a ge si e while imp o ing i s bioa ailabili y. Aboudzadeh
e al. in h ee s udies (published in his Special Issue) explo ed he solubili y, pe me-
abili y, o al bioa ailabili y, and he apeu ic e ec i eness o di e en d ugs h ough hei
Polyme s 2022,14, 1178. h ps://doi.o g/10.3390/polym14061178 h ps://www.mdpi.com/jou nal/polyme s
Polyme s 2022,14, 1178 2 o 4
encapsula ion wi h polyme s, in ending o achie e an enhanced d ug elease. In he i s
s udy, lignin he second mos abundan biopolyme on ea h (a e cellulose) was used
o encapsula e doxo ubicin (DOX) in oil-in-wa e (O/W) mic oemulsions o enhance he
bioa ailabili y o DOX. The au ho s demons a ed ha encapsula ion and slow elease o
DOX enhanced he cy o oxic e icacy o his an h acycline agen agains cance cells bu did
no imp o e i s sa e y owa ds no mal human cells [
3
]. In ano he epo , Aboudzadeh e al.
designed a deli e y sys em based on e hylcellulose (a biobased polyme ) nanosponges ha
could imp o e he o al bioa ailabili y o Olmesa an medoxomil, one o he p ominen
an ihype ensi e d ugs. I was shown ha he op imized nanosponge d ug ca ie p e-
sen ed a be e -sus ained elease wi h imp o ed an ihype ensi e e icacy and an i umo
ac i i y agains A549 lung cance cell lines [
4
]. In he las s udy, h ee hyd ophilic polyme s,
namely Kollipho
®
P188, Kollidon
®
30, and Kollidon
®
-VA 64 (ob ained om BASF Co.,
Ludwigsha en, Ge many) we e employed as d ug ca ie s h ough solid dispe sion (SD)
app oach o encapsula e Sildena il ci a e, a equen ly used medica ion (unde he b and
name Viag a) o he ea men o e ec ile dys unc ion (ED). The au ho s concluded ha
he op imized SD sys em exhibi ed supe io ac i i y and was a p omising s a egy o
imp o ing solubili y, dissolu ion a e, and aph odisiac e ec s on male a s [5].
Ano he poo ly wa e -soluble d ug, a emisinin, was o mula ed by Na esan e al.
in o nanomicelles using poly inylpy olidone (PVP K90) and a polyme ic su ac an
(
Poloxame 407
). A emisinin-loaded nanomicelles p esen ed a no able an i-angiogenic
ac i i y compa ed o a emisinin suspension. The au ho s p oposed his o mula ion as
a po en ial ea men o age- ela ed macula degene a ion (AMD) [
6
]. In ano he epo
published by Sylwia Łukasiewicz, clozapine he second-gene a ion an ipsycho ic d ug, was
encapsula ed wi hin polyme ic nanocapsules using an anionic su ac an (sodium docusa e)
and bio-compa ible polyelec oly es such as poly-
L
-glu amic acid (PGA) and poly-
L
-lysine
(PLL). The ou e laye o he ca ie was g a ed by polye hylene glycol (PEG). Acco ding
o he au ho , his app oach may acili a e he a ailabili y and sa e y o he d ug, enhance
he selec i i y o i s pe o mance, and subsequen ly inc ease he e iciency o schizoph enia
he apy [7].
Nowadays, one o he main issues in mic oencapsula ion p ocesses is ob aining a
s able p oduc du ing s o age wi h consis en encapsula ion and elease e icacy. The la e
equi emen is ela i ely di icul o achie e because o he sensi i i y o common ma e ials
(used o ma ix o mula ion) o p ocessing and en i onmen al ac o s ha could lead
o poo encapsula ion e iciency, sho mic ocapsules shel -li e and uncon olled elease
kine ics. In his con ex , na u al polyme -based ca ie s (wi h co e–shell s uc u e) ha e
p esen ed mul i unc ional capabili ies and enabled he simul aneous encapsula ion o ac i e
agen s o di e en physical/chemical p ope ies o hei a ge ed deli e y and sus ained
elease. Design o mic o- and nano-me ic co e–shell capsules and po ous sphe es made o
na u al polyme s (e.g., such as polysaccha ides and polypep ides), hei unc ion-speci ic
aspec s, mechanisms o o ma ion, challenges, and u u e pe spec i es a e discussed in a
e iew pape w i en by Gedanken e al. published in his issue [8].
Ano he in e es ing ype o polyme s a e hyd ogels, which a e u ilized in many ields
and mo e pa icula ly in he biomedical ield whe e hey can unc ion as d ug p o ec o s,
a ge able ca ie s o bioac i e agen s, e c. Jean-F ançois Gohy e al. con ibu ed in
his issue by de eloping a new class o edox- esponsi e hyd ogels by combining 2,2,6,6-
e ame hyl-1-pipe idinyloxy (TEMPO) s able ni oxide adicals and oligoe hylene glycol
me hyl e he me hac yla e (OEGMA). The au ho s showed hese polyme ic ne wo ks can
be success ully used ei he o he elec ochemically igge ed elease o aspi in o as
ca alys s o he oxida ion o p ima y alcohols in o aldehydes [
9
]. Va ious chemical and
physical s imulan s may se e as igge s o d ug elease. Va ia ions in ionic s eng h and
ionic composi ion combined wi h pa hological p ocesses may p o ide igge s o cause a
ca ie esponse. Recen de elopmen s and no el s a egies in designing ion- esponsi e
d ug deli e y sys ems including a a ie y o s uc u es we e e iewed by Musiał e al. [
10
].
Ano he ype o sma ma e ial is phase-changing ma e ials (PCMs). Mic oencapsula ion
Polyme s 2022,14, 1178 3 o 4
is an applicable p ocedu e o conse e and e ain he cha ac e is ics o PCMs ha a e
used in he mal ene gy s o age applica ions. Sku ky e-Papie iene e al., in an in e es ing
s udy, imp o ed he he mal pe o mance o pa a in PCM mic ocapsules (consis ing o
a polyme ic melamine- o maldehyde) o ex ile applica ion by modi ying hei ou e
shell [11].
Despi e hese c ea i e epo s in he ield o sma polyme s, he need o c ea e new
polyme la ices has always exis ed owing o he b oad ple ho a o indus ial applica ions
in ol ed. Acco ding o his necessi y, Cappelle i e al. de eloped bu yl me hac yla e-based
la ices ia ee adical polyme iza ion in wa e by adding (i) me hac ylic acid/me hyl
me hac yla e and (ii) me hac ylamide, espec i ely, as an aqueous phase in Picke ing
emulsions. Bo h syn hesized la ices displayed p omising cha ac e is ics as p o ec i e
polyme shells o he con olled deli e y o ac i e agen s [12].
F om an enginee ing poin o iew, he con inuously inc easing demand o cos e-
duc ion, oge he wi h sho - ime p ocesses is leading o subs an ial esea ch de elopmen s
in new me hods o loading bioac i e agen s. The coa ing con aining bioac i e agen s is
one o he mos success ul app oaches o enginee ing ma e ial su aces while keeping
bulk p ope ies. An in e es ing a icle o his issue epo s di ec deposi ion o poly(ac ylic
acid) coa ings con aining a ious agen s (e.g., dyes, luo escen molecules) h ough ae osol-
assis ed open-ai plasma me hod. In his wo k, Man o ani e al. employed his one-s ep
p ocess po en ially o encapsula e a unable quan i y o any sensible wa e -soluble agen
wi hou changing i s ac i i y. They p esen ed his app oach as qui e appealing o designing
speci ic d ug- elease sys ems [13].
Finally, he las con ibu ion o his Special Issue ocuses speci ically on he signi icance
and eme ging ole o nano echnology o ea pollu an s in wa e (e.g., 4-NP and mo in) and
imp o e i s quali y. In his s udy, amphiphilic polye hyleneimine (PEI)-oleic acid micelles-
s abilized palladium nanopa icles we e syn hesized by Wang e al., which e ec i ely
ca alyzed he educ ion o 4-NP o o m 4-AP and had high ca aly ic e iciency agains
mo in. The au ho s concluded ha hese nanopa icles ha e g ea po en ial applica ions in
ea ing a ious o ganic con aminan s in solu ion in he u u e [14].
In iew o he abo e summa y and discussion, we belie e ha he p esen Special
Issue explo ed he la es esea ch on he unc ion o polyme s in encapsula ion echnology
including undamen al heo y and expe imen s oge he wi h e iews and a icles. Mo e
e icien designs and p epa a ion p ocesses, as well as u he unde s andings o he
in e acial chemis y o encapsula ed ma e ials wi hin he polyme ic sys ems, a e needed.
Au ho Con ibu ions:
Bo h gues edi o s w o e he edi o ial and app o ed he inal e sion. We
hank all he con ibu o s as well as he edi o ial s a o Polyme s o hei e o s: M.A.A. and S.H.
All au ho s ha e ead and ag eed o he published e sion o he manusc ip .
Con lic s o In e es : The au ho s decla e no con lic o in e es .
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2.
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Khodei , M.; Jia, H.; Vlad, A.; Gohy, J.-F. Applica ion o Redox-Responsi e Hyd ogels Based on 2,2,6,6-Te ame hyl-1-
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Sku ky e-Papie iene, V.; Ab ai iene, A.; Sankauskai e, A.; Rubeziene, V.; Bal usnikai e-Guzai iene, J. Enhancemen o he The mal
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Saba ini, V.; Pellicano, L.; Fa ina, H.; Pa gole i, E.; Annunzia a, L.; O enzi, M.A.; S o i, A.; Cappelle i, G. Design o New
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